1. Field of the Invention
The present invention relates to zoom lenses of the type consisting of four lens groups of positive, negative, positive, and positive power arranged in this order as viewed from the object side and is directed to improvements in this type of zoom lenses.
2. Description of the Prior Art
Examples of the above mentioned type of zoom lenses are disclosed, for example, in Japanese Patent Publication No. 31,818/1970 the counterpart of which is U.S. Pat. No. 3,615,125 and Japanese Pat. Laid open No. 131,852/1978. In these known zoom lenses, focusing is generally achieved by moving the most object side positive lens group. However, their focusing ability for close distance photographing is not satisfactory.